Refinishing tool for crankpins



Sept. 21, 1943. I R. J. WILSON 2,329,806

REFINISHING TOOL FOR CRANK PINS Filed March 15, 1941 2 Sheets-Sheet 2 M I Z y! w lNVE TOR ATTORNEYS Patented Sept. 21, 1943 4 Claims.

dismissed n muted States! Letters Pat 'tfig.

weer often tends-to-eorekthe pins. Inanyt'eveht it "is e cessary that sumeient metalflbe 'moved ffgrh the pin in 1- order to; bring I it backto a true" Qylingirieekbearing which-will be smooth tothel .flflgi'yfbhe protective oil can 'be maine tamed between the creek pin" amt the crank? pin.

heeringry i: gt present the norr ri al method 10f refinishingi t bearings is; to gremove, the shaftdrom the;

hginwfand togset it upin a latheof suifioientsizeso that theer-ank pin bearing-s oan be -re-i volyed about theirdongitudinal"axis. All this e rl-tails expensive skilled- 1abor and in some instances; where-yew large: 'crank-shafts' areiiinder consideration, facilitiesare :not' raidily available that have the -capacityi to handle such ittorkr It is under such onditions' that my era'hii 'pifi refinishing *tooirserves to the utiilost. The tool iteelimay Jo' produced verytheably and ihtheQ iarits ohe' o'ain be -'cari"ied withw-th fiowr fil'eiri'ft '56 that refiairs Rial'ri 50* m 'eonstriie on strict Still another object of my preemi Vehtiofi I employed in mir cutti g tool I Figure 3= is avertieah-sectiohat View throfih a- -cylinder of an internal'combustion engine shiotvingv the manner" in "which my precision tool- Figure '4; is aside' elevation; of =m'y'too1'; 1

Figure 13 is a cross-sectional view taken along the line |3|3 of Figure 9.

Referring to the drawings, throughout which like reference characters indicate like parts, l4 designates the main body or base of my refinishing tool. This is preferably cast of suitable metal and is of the same general dimensions normally as the crank pin bearing used on the pin to be refinished. Base M with this end in view is provided with a machined upper surface 15 and a plurality of studs I6 which are adapted to engage the lower foot of the connecting rod IE, or if the refinishing is not to be done with the crank shaft in the engine bed, then a suitable lever should be secured thereto so as to prevent rotation of the tool. The base should be of sufiicient extent to encircle approximatelyone-half of the crank pin. One side is pivoted, at 26, a retaining member 22. This member is provided preferably with a liner as 23 of bearing metal so that it will have no tendency to score the bearing. At its opposite end retainer 22 has pivotally secured to it as at 24 a single tension member or a plurality of tension members 25. Base I is provided with a bearing member or liner 26 which is complementary to liner 23 and is secured to thebase as by one or more screws 28. An adjusting means is provided by a plurality of screws which are threaded into base [4 so that the extreme end 3| of liner 26 can be forced inwardly so as to adapt the liner more closely to the crank pin bearing particularly after machining has reduced the diameter of the pin. An exaggerated adjustment of this liner is indicated in Figure, 12.

On its opposite side basev M has a V-shaped groove 33 machined therein in a manner to be parallel with the axis of the crank pin. Adapted to seat in groove 33; with reasonable clearance, is a V-shaped ridg 34 formed as part of tool holder 36. A plurality of tap screws 38 are disposed alined with ridge 34 and are tapped into base M. The holes through which they pass into holder 36 are made somewhat larger than the body size of the screw so that the tool holder can rock slightly within groove 33 as adjustment requires. This arrangement is probably best shown in Figures 9 and 10.

At its lower end, as shown in my various views, tool holder 36 is provided with a seat for the cutting tool or blade 46. This seat as will be observed in the different views is provided with a rest portion at 42 which is accurately machined so that the cutter or blade 40 may be accurately alined with the axis of the crank pin which is generally designated bythe reference characters P. A plurality of set screws 44 are alined with the base of cutter 4D and are threaded into the tool holder 36 in such a manner that by adjusting the screws the cutting edge of cutter 40 may be accurately positioned and once positioned, accurately maintained in that position. To clamp cutter 40 in position I provide the clamp bar 46 which is in turn held in place by a plurality of cap screws 43. These screws pass through body size holes in holder 36 and are threaded into bar 46. It will be observed from the drawings that bar 56 is provided with tapering sides as 56 and 5l' so that as the bar is pulled down into the holder by screws 48 it will wedge into position and thus securely hold cutter 46 in its adjusted position.

After cutter 46 has been positioned and clamped the entire tool holder 36 may then be adjusted to give the depth of cut desired or to,

.8 to 12, inclusive.

make successive cuts as required. This is accomplished by providing a plurality of screws 53 which pass through slightly oversize holes in holder 36 and are threaded into base 14-- so that they can be adjusted to move the tool holder to the left as viewed in the various views To resist the action of screws 53 and 38 I provide one or more screws 55 which is threaded into holder 36 and which bears against the face of base I4. In this manner holder 36 may be securely held in an adjusted position where it is spaced away from base l4 except for the engagement of ridge 34 with groove 33.

Holder 36 is provided with one or more, as desired, bifurcated bosses 61 which is placed to form a seat for nut 58. Tension on this nut, in turn, clamps retainer 22 in position.

Method of operation While it will be apparent, it is believed, that my refinishing tool might be adapted to minor variations from a standard size it is normally intended, particularly injthe "larger sizes, that the tool will be particularly adapted to the size crank pin it is to refinish. This is usually the more satisfactory manner in that the size of crank pins vary through wide limits and the length of the bearing for the same size. will vary in different makes of engines. Consequently, base l4 would normallybe adaptable to but'a limited range from the particular pin, it isde-' signed for. In orderto secure accurate seating of my tool, the liners 23 and 26 should normally be machined with' reasonable accuracy to fit a particular crank pin' to be finished. l

Thenext step is tofit my'refinishing tool to the crank pin in question; This is done bythe proper adjustment of the cutting blade! by means of screws 44 clamping the-same in place by means of screws 48 and then to adjust holder 36 in a fixed position by "means of its adjust ing screws. It will be no'ted that the extreme end of cutter' lfl canbe ground to any desired radius so that a fillet canbe provided at each end of the crank pin having the exact radius de sired. These too" will be smoothly and accurately finished as is the crank pin.

It necessary thento provide means which will prevent my refinishing tool from revolving.

If the work is being done with the crank shaft in the engine bed then my tool can'best bese cured to the connecting rod 18 after the showing of Figure 3 and the piston used as a cross-i head or guide. If the crank shaft on the other handis out of the engine andet up as in a lathe or on V-blocks or other'suitable bearings that will permit it-to revolve, then a reasonably long lever should be secured by means of studs 5 and then either blocked or held against movement.

With my refinishing tool thus in position and with the retaining member 22 secured in position,

of the crank pin, due tothe fact that it has been, found to be most satisfactory to take a very light.

out from the pin. Afterone out istaken around the pin it may be found that the-pin hasnotbeen entirely cleaned up or reduced to a true cylindrical surface andby adjustment of the tool holder 36 successive cuts "are taken until a true cylindrical hearing has been achieved. In following out this method the shaving removed from the shaft will normally be paper thin, normally from 1/1000 to 3/1000 of an inch and it is because of this relatively thin shaving that the work can be done by hand and further all chattering or tool markings on the crank pin is avoided. The crank pin as completed will present a true smooth surface which will lend itself readily to maintaining the oil film that is so essential to a bearing of this character if long useful life is to be expected of it.

It is desired to point out that due to the fact that the work is not done rapidly as though it were in a lathe, the operator can observe the functioning of the tool at all times and, using the proportions shown, there is ample space provided for any accumulation of metal that is removed from the crank pin. When the pin has been reduced to a true smooth cylindrical surface my refinishing tool has completed its function and may be removed.

The foregoing description and the accompanying drawings are believed to clearly disclose a preferred embodiment of my invention but it will be understood that this disclosure is merely illustrative and that such changes in the invention may be made as are fairly within the scope and spirit of the following claims.

I claim: 1

1. A tool for refinishing crank pins in place in an engine, said tool comprising a base adapted to be secured to the lower foot of a connecting rod in an engine and having a jaw to encircle substantially one-half of a crank pin, a flexible liner secured in said jaw and said base having means for inwardly flexing said liner to provide a curvature thereof that will accommodate the liner to a substantial portion of the surface of a crank pin to be refinished, a retaining latch link pivoted to said base on one side of the jaw and adapted to further encircle a crank pin to be refinished, a tool holder rockably secured to said base across the jaw from the point of pivot of the retaining latch and having a movable tool blade to engage the face of a crank pin, means for moving the tool blade to advance it into thework without moving the holder, and a tension member between said retaining latch and said tool holder adapted to draw the tool base and latch link about a crank pin to position the tool blade to shave a cutting from the face of the crank pin.

2. A tool for refinishing crank pins in place in an engine, said tool comprising a base adapted to be secured to the lower foot of a connecting rod in an engine and having a jaw'to encircle a portion of a crank pin, a flexible liner secured in said jaw, said base having means for inwardly flexing said liner to provide a curvature thereof that will accommodate the liner to a substantial portion of the surface of a crank pin to be refinished, a retaining latch link pivoted to said 7 base on one side of the jaw and adapted to further encircle a crank pin to be refinished, a tool holder rockably secured to said base across'the jaw from the point of pivot of the retaining latch and having a tool blade to engage the face of a crank pin, and a tension member between said retaining latch and said tool holder adapted to draw the tool base and latch link about a crank pin to position the tool blade toshave a cutting from the face of the crank pin.

3. A tool for refinishing crank pins in place in an engine, said tool comprising a base having a jaw adapted to encircle substantially one-half of a crank pin, a flexible liner secured in said jaw and said base having means for inwardly flexing aid liner to provide a curvature thereof that will accommodate the liner to the surface of a crank pin to be refinished, a retaining latch link pivoted to said'base on one side of the jaw and adapted to further encircle a crank pin to be refinished, a pivoted tool holder on said base across the jaw from the point of pivot of the retaining latch and having a tool blade to engage the face of a crank pin, and a tension member between said retaining latch and said tool holder adapted to draw the tool base and latch link about a crank pin to position the tool blade to shave a cutting from the face of the crank pin.

4. A tool for refinishing crank pins in place in an engine, said tool comprising a base having a jaw adapted to encircle a portion of a crank pin, means in said jaw to provide a curvature thereof that will accommodate the jaw face to i the surface of a crank pin to be refinished, a

retaining latch pivoted to said base on one side of said jaw and adapted to further encircle a crank pin to be refinished, a tool holder rockably mounted on said base across the jaw from the point of pivot of the retaining latch to engage the face of a crank pin, and a tension member between said retaining latch and said tool holder adapted to draw the tool holder and latch link about a crank pin to maintain the tool blade in position to continuously shave a cutting from the face of the crank pin.

ROBERT J. WILSON. 

